HIGHLIGHTS
The introduction of posttransplant cyclophosphamide (PTCy) has increased haploidentical transplants, prompting research into the impact of HLA epitope mismatches on transplant outcomes.This retrospective study analyzed 1037 patients from a Japanese registry (2011–2019) who received haploidentical peripheral blood stem cell transplants with either PTCy or antithymocyte globulin-based GVHD prophylaxis.In high-risk patients receiving PTCy, higher class I PIRCHE scores were linked to lower relapse risk and improved overall survival, while in standard-risk patients receiving antithymocyte globulin, higher class II PIRCHE scores were associated with reduced nonrelapse mortality and better survival.The study highlights the differential impact of T-cell epitope matching based on GVHD prophylaxis and suggests that pretransplant disease status influences the graft-versus-leukemia effect in haploidentical HSCT.
